Alan (Lord of the Rings... or are you tired of hearing about Peter Jackson...

All is forgiven when you bring your Gold AMEX as a tourist. And you suckers actaully paid to watch three of our three-hour tourism commercials...

Quote:

Originally Posted by leviathon

I wonder why no markings? Early production?

That could be the case. It is often done as a cost saving measure (NOTE: I'm not suggesting that that is the reason here). False economy in my view. Sometimes, the component legend is left off by mistake.

If you send me a good high res digital pic of the topside of your SA5 I'll do my best to mark up the relevant components. By hi res, I mean use a camera with >= 4M pixels. At the risk of teaching you to suck eggs ... you might be a pro photographer during the daylight hours... use the macro facility, diffuse lighting, a tripod, and turn the flash OFF. Then use the delayed timer so that your shaking hands don't blur the resulting long exposure. Then send it by PM.

__________________
Alan
"If you can not measure it, you can not improve it" - Lord Kelvin

Hi Alan,
Good thought. I haven't bothered taking a picture of these, but it might be a very good idea to do so. The earlier Counterpoint products are poorly documented and getting everything straight before the memory fades is pretty smart.

Quote:

Naturally I prefer my solution - use the maximum recommended cap but add in a build-out resistor

Can't say as I have a problem with that idea. I prefer lower value capacitance because the high frequency characteristics are better - all other things being equal. You are looking after two of the problems associated with large filter capacitor sizes by adding resistance in series. Thing is, some ripple in the first filter stage isn't a bad thing. I feel many of us have been taught to fear this as an inherent bad thing. It isn't, and it took me a while to figure this out on my own. Many good engineers have already sorted this out.

Hi Ed,
The Counterpoint preamps sound pretty good as far as I'm concerned. Then again, compared to the crop of pretty bad sounding newer tube equipment a Counterpoint begins to really shine. Truly, once the design issues are put to bed, they are reliable, good sounding units. Well worth doing the work and keeping them.

Just make sure you don't have the "toroid upgrade" done. The same goes for blindly following M.E.'s modifications he has posted on the web. The man is still making a living off the same product that went out the door ages ago. What a cool trick!

As for your location, I'm not sure. If you run into real trouble, you do know where I am at least. That's what I was attempting to figure out, if you were close enough to help should you need it.

Hi Chris,
Sorry my city location hints didn't help. Guess we are in a more sad part of the country than I thought! Would capital of Manitoba help? We used to be quite a hot spot for audiophiles late 70's and early 80's.

Thanks for you offer for assistance. And the heads-up to not go overboard on pre-amp (M.E.) upgrades. Sometimes I need to be reeled in.

Hi Alan,
Been crazy week here and not even half way through it. Will get to the pics on the weekend. I can either pull out my old Pentax Spotamatic II, a little Canon Digital Camera I have on hand, or tell my future daughter-in-law how neat it would be if she took a still of a really cool pre-amp with her Canon Rebel. Maybe I can tell her the preamp is made by Prada!

All... now that I look back at everything we've gone through, you're gonna love this... what's your opinion on the SA5/SA5.1? Would one have to go to great expense to find something comparable in the new market? Sorry if I am out of line here, asking opinion on sound rather than DIY repair.
Ed

It is a damn fine sounding preamp. If you have had it 20 years then it owes you nothing and spending some time (keep it fun) and a some money will reap huge rewards. I can't imagine you doing better for what you are likely to spend in parts on it.

I'm biased - I also think it looks purdy too.

I would be wary of going out and buying one with the view to upgrading it though. It may seem a travesty, but I see anything of that vintage as no more than a case donor. But then I already have too many 'collectibles' awaiting some TLC...

__________________
Alan
"If you can not measure it, you can not improve it" - Lord Kelvin

oh oh. doing some readin on the net. looks like there was a time and place where the PF caps were a good option compared to what was available at the time. That was then. Now the construction ain't what it used to be and much better options available.

Scary thought I would have left em in there.

I get to do more soldering!

ED

Photo flash capacitors were popular in the early 80's and up into the mid 80's. Then they found that the PF caps degraded, to a dangerous state, sometimes...very quickly.

If for example, you try them in a loudspeaker passive crossover, you will find that they degrade in as little as a few weeks.

__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan. Sometimes the claims aren't extraordinary. Sometimes the weakness of men's minds are the culprit. Mass mentality has nothing to do with obviousness or truths.

Hi Ed,
No problem. Me dense. I gave up trying to follow sports years ago. Running my own business didn't allow me to have any continuity at all.

You still have the audiophiles. They are just quiet for now. My guess is that the consumers are simply tired of being lied to as much as they have over the last 30 years or so. The industry worked very hard for a long time in order to lose our confidence. Short term gains have now presented the flip side.

Hi Ken,

Quote:

Photo flash capacitors were popular in the early 80's and up into the mid 80's.

Absolutely!!

I spent years undoing the damage. Most of the proponents of flash capacitors were the stereo shops and repair dudes that were caught up in what the audio mags had to say. Problem is (as you've pointed out), the photo-flash capacitor was never designed to operate as a filter capacitor. This had nothing to do with quality and everything to do with internal design. The only reason photo-flash capacitors became "in vogue" was the price. That's all. For some reason, and even today, audiophiles latch on to cheap things and use them. Cheap CD players for transports, cheap capacitors - you name it! I'll never understand what rational explains why something that is inexpensive is supposed to out-perform the correct device / part for the job.

Quote:

If for example, you try them in a loudspeaker passive crossover, you will find that they degrade in as little as a few weeks.

Just dropping a line that haven't had a chance to correspond, send pics (Alan). Working weekends. Not even chance to listen to stereo. Good news I finally hired some help. I am officially a 2 person company. Miss the forum, but back soon.

Ahhhhh. Turned my preamp on after a month or so of happiness and ... badda boom. 5651 didn't light up! And that all so familiar smell of something crispy. However I am going to sum up 5 hours of hair pulling in this...

I checked the usual suspect resistors, though fine, replaced them with big steroid replacements I had been meaning to. All tubes fines except (again) 6JC6A tube rejected! This is the 4th one now I think that was taken out. Replaced that. Turned on... worked fine but then I saw a spark. Where...? Of course between the vertical and horizontal board right in the vicinity of the 6JC6A. Solder-test-solder test... wiggle board... 5651 till intermittent, (all with lights turned out so I can see the lightshow. Husband down in the basement in the dark again burned carpet with soldering gun)... on... clean... resolder... Ed has meltdown... you know what... I finally unsoldered the darn vertical circuit board right off. Included removing 6 screws it took all of 15 minutes. I know it will take me longer to clean and reassemble but WHAT A STUPID WAY to connect 2 circuits boards so (the tubes can lay parallel?) I don't know what it was done that way.

Anyways I am glad I have gone nuts.

If nothing else, I am going to fix all those contacts once and for all!

Hi Ed,
Yes, that was one of the main issues with that design. I completely agree with you that it was constructed stupidly. There should have been wires run across the connection point, dual for heater connections. There are also possible problems with where the umbilical wires connect to the board. The power unit has more issues as well, solder joints being one of them.

It shouldn't have killed your 6JC6A though. I've seen it take out the pass tube before. One thing you should check since I'm thinking of it. Check that the current regulator diode is okay. Also make sure the voltage across it is about 45 VDC. This is a very approximate figure. The important thing is that these parts are rated for 100 VDC maximum, and they need at least about 10 VDC across them in order to regulate properly. There should be a fixed resistor in series with the diode (actually a J-Fet) that determines how much voltage is dropped across the diode, the balance of which will be found across the resistor. This voltage drop is very dependent on the value of your AC mains. If there isn't a zener diode across this part, use a 5 watt, 91 V zener across the current regulator diode. It will conduct before the part breaks down, but then you have another problem in that the current is uncontrolled. Let's hope the series resistor goes open before dead tubes start popping up. What failed in that tube? Did it arc inside?

Ed, your rant is perfectly justified. I've done so many times myself and they weren't even my units. I guess I should examine how this power supply is designed as well. The SA-5000 has serious design issues as well, and it does blow up the error amp tube (12AX7A). You have to use a good, quiet one in that location (= expensive).